(CNN) -- Two international bridges between Venezuela and Colombia remained closed, as Venezuelan authorities searched for three people and arrested a fourth suspected in the shooting death of two national guardsmen.

Their killings on Monday marked the most recent in a series of events that have raised tension between the neighbors.

The closure of the Simon Bolivar and Francisco de Paula Santander international bridges in central-west Venezuela created a scene of confusion for the area's residents and merchants.

Some clashes between guards and residents were reported. News footage showed people crossing the border on foot, carrying goods and luggage on their backs across a shallow river.

"The paramilitary phenomenon that was created in Colombia has permeated our border and has intensified in the past year," Venezuelan Vice President Ramon Carrizalez said at a news conference.

The Colombian government is complacent toward the paramilitary activity, which is aimed at destabilizing Venezuela, he said.

The paramilitary phenomenon that was created in Colombia has permeated our border and has intensified in the past year-- Venezuelan Vice President

Colombian authorities have not responded to the claims.

Speaking in the border state of Tachira, Carrizalez said that the arrested man, who was not identified, will be turned over to the courts.

Relations between Colombia and Venezuela have been rocky since the summer. In August, Colombia accused Venezuela of supplying guerillas with shoulder-fired anti-tank weapons. Such weapons seized from the Revolutionary Armed Forces of Colombia, or FARC, had been traced to Venezuela, Colombia said.

The FARC has been fighting the Colombian government for more than 45 years. Chavez, at the time, said the accusation amounted to blackmail.

Last month Venezuelan authorities said they captured two Colombian spies. Colombia denied the announcement.

Chavez has also been a vocal critic of an agreement signed between the United States and Colombia that allows U.S. personnel to be stationed at seven military bases there.

Chavez has likened the agreement to an act of war and accused the United States of wanting to stage military personnel nearby to destabilize his leftist government.

Most recently, in the same area as this week's bridge closures, Venezuelan authorities found the murdered bodies of 10 men that Colombia described as an amateur soccer team that had been kidnapped near the border. Vice President Carrizalez said the men were paramilitaries.